Mounting for guns carried by aeroplanes and similar aircraft.



T. S. DUNCAN.

MOUNTING FOR cums CIARRIED BY AEROPLANES AND SIMILAR AERCRAFT.

APPLICATION FILED MAY 24, 1917.

Patented Apr. 1,1919.

THOMAS SMITH DUNCAN, OF LONDON, ENGLAND, ASSIGNOR TO VICKERS LIMITED, OF WESTMINSTER, ENGLAND.

MOUNTING FOR. GUNS CARRIED BY AE Application filed May 24, 1917.

To all whom it may concern:

Be it known that I, THOMAS SMITH DUN- CAN, a subject of the King of Great Britain, residing at Vickers House, Broadway, Westminster, in the county of London, England, have invented certain new and useful Improvements in or Relating to Mountings for Guns Carried by Aeroplanes and Similar Aircraft, of which the following is a specification.

This invention relates to mountings for guns carried by aeroplanes and similar aircraft. When the aeroplane carrying the 'gun is in motion and the gun is being trained from its ahead position, the pressure of the air on the gun will exert a turning moment tending to swing the gun about its training pivot until -it reaches a position pointing dead astern, this turning moment reaching the maximum when the gun is at right angles to the line of flight of the aeroplane.

According to my invention means are provided for balancing or approximately balancing the aforesaid turning moment so that the training of the gun can be effected without requiring the operator to exert an effort to overcome the turning moment, the said means comprising a spring connected to or operated by a crank or equivalent angularly displaceable member which derives its motion from the training movement of the gun and moves in synchronism therewith, the spring exerting upon the gun, through the crank, a turning moment opposite and equal or substantially equal to that exerted upon the gun by the air at all angles of training of the gun. The said spring may comprise a metal tension spring or one or more rubber cords anchored at one end and connected at the other end to the pin of the crank. The angular position of the crank in relation to the gun is such that when the gun is pointing dead ahead or astern the spring or rubber cord, the crank pin and the axis of rotation of the crank, will lie in a common plane, in which case the spring will not exert any turning moment of the gun, while when the gun is pointing at right angles to the line of flight, a plane containing the axis of the crank pin and the axis of the crank will be at right angles or approximately at right angles to the aforesaid plane, in which event the spring will be exerting the maximum turning moment on the gun.-

Specification of Letters Patent.

norLAnEs AND SIMILAR AIRCRAFT.

Patented Apr. 1, 1919. Serial No. 170,621. I

In order that the said invention may be clearly understood and readily carried into effect, the same will be described more fully with reference to the accompanying drawings, in which Figure 1 is a diagram showing the main features of the balancing means.

Fig. 2 is a plan of a constructional form of the balancing means.

Fig. 3 is an end view of the movable bar or frame (hereinafter referred to) of Fig. 2 and the parts carried thereby, and

Fig. 4 is a view similar to Fig. 2 showing a slightly modified form of the balancing means.

Referring to Fig. 1, A is the gun and A is a ring moving with the gun in training; B is a pulley to which movement is transmitted from the ring A, during the training of thegun, by a flexible rope or cord B passing around the ring and'the pulley. Z) is a pinion connected to the pulley B and meshing with a gear wheel 0 upon which a crank pin C is mounted, the said gearwheel thus constituting the aforesaid crank. D is the spring anchored at one end and connected at the other end to the crank pin C.

The ratio of the diameters of the gear wheel,

the pinion, the pulley and the ring is such that the gear wheel makes one revolution during the time that the gun is being trained through a complete circle. The gear wheel is adjusted in relation to the ring until when the gun is pointing in the directionof flight of the aircraft as shown (this direction being indicated by the arrow in Fig. 1) the spring I), the crank pin C and the axis of the'gear wheel 0 will lie in a common plane so that the spring will then not exert any turning moment on the ring A. When however the gun is trained from its ahead position the spring will exert a turning moment on the gun opposite and equal or substantially equal to the turning moment due to the pressure of the air on the gun, this turning moment reaching the maximum when the gun lies at right angles to the direct-ion of flight.

Referring to Figs. 2 and 3, the gear wheel 0, the pinion I) and the pulley B are horizontally arranged on a bar or frame C which is slidably mounted on the members a, 0 of the fuselage and is adjustable toward and away from the rin A by bolts C, G and nuts 0 inor-er to tighten and slacken the wire rope or cord B as required, the anchorage'forthe spring or rubher cords D being also carried by the said bar. In this manner ifthe gear wheel carrying the crankipin 0 should become out of step with the gun, the wire ro e or cord can 7 be temporarily slackened' su ciently to en'- able'the gear wheel 0 to be angularly displaced relatively to the ring A to the required extent. The said ring is of channel shapem cross-section and the w1re rope or cord is disposed in the channel.

In-Fig 4 the spring D as well as serving to balance or approximately balance the upon the saidbar or frame aforce tend ing to move it away from the ring A. One

end of the bar or frame is pivoted at C to one ofthe members 0, 0 of the'fuselage and the-other end is slidably supported at 0 by the other one of these members. i

The aforesaid ring Apreferably constitutes the part upon which the side members 7 of a'frame' carrying the gun are pivoted, the said ring-being 'rotata-bly mounted at the upper'part of afwell or chamber 'in' which takes the place of the'rotatable ring; it can the'gu'nner is accommodated, V tjlon can howeverbe employed 1n connection The invenwith a gun mounting in which a turntable also be equally well employed with other forms of -mounting, in which case thecrank maybe directly connected to apart moving with'the gun in training or may be suitably [geared to the said part, It is also to be understood that the invention can be employed with guns moving through a limited angle of tralning as well as with guns having an all-round training movement.

co ies of this patent may be obtained for i What I claim and desire to secure by Letters Patent of the United States is 1. In an aircraft gun mounting, the comblnatlon of a crank member, a spring connected to the pin of this member, a rotary member moving in'training with the gun, a

pulley interposed between said crank member and the rotary member and a flexible member passing around said rotary member and pulley. g 2. In an aircraft gun mounting, the combination of a crank member, a spring connected to the pinof this member, a rotary member moving in training withthe gun, a pulley interposed between said crank mem ber andthe rotary member, a flexible member passing around said rotary member and pulley and abar upon which said crank member is mounted, this bar being movable toward and away from the rotary member. 3. In an aircraft gim mounting, the com bination of a crank member, a spring connected to the pin of this member, a rotary member moving in training with the gun, a pulley interposed between said crank memher and the rotary member, a flexible mem-' ber passing around said rotary member and pulley and means whereby said spring resiliently holds the pulley away from the rotary member so as to hold the flexible member taut. I 7

4:. In an aircraft gun mounting, the com bination of a crank member,a spring connected to thepin of this member, a rotary member moving in. training with the gun, a pulley interposed between said crank mem ber' and the rotary member, a flexible member passing around said rotary member and pulley, a bar upon which said crank member and pulley are mounted and meanswhereby said spring holds the bar away from the rotary member so as to hold the flexible membertautp. 7 r In testimony whereof, I affix my signature.

THOMAS SMITH DUNCAN.

five cents each, by addressing the Commissioner. of Patents.

Washington, D. 0. 

